The newest addition (following “Pay Up,” “Hell Meets Harry Halfway,” “Gentlemen Volunteers” and “Poet in New York”) to the touring repertory of dazzling intellectual vaudevilles from Philly-based experimental company Pig Iron is “Chekhov Lizardbrain.” This “menagerie of human possibility” is deeply moving as well as very funny. The four performers and co-creators are the hard core of this adventurous troupe, and as our narrator, Chekhov, explains, “we put the human condition on stage and make it dance.”

As, of course, did Chekhov. Riffing on “The Cherry Orchard” as well as “Three Sisters,” Robert Quillen Camp’s script becomes surprisingly Chekhovian, despite its po-mo style and its neuroscientific investigations. The brain is the hot topic these days, and the debt here is to Paul D. MacLean’s “triune brain theory,” which holds that below the humanizing neocortex is the “paleomammalian,” much like a pig or dog’s brain, and below that is the reptilian brain, the human brain stem.

Borrowing, too, from Temple Grandin’s bestseller, “Animals in Translation,” the show explores the separate subjectivity of each brain. Or, as Chekhov Lizardbrain tells us, “You want to know something? You gotta have something to know it with.” And then to complicate things further, Memory shows up — in the form of a tiny house under Chekhov’s top hat, “the house in your head.”

The three actors represent not only three brothers but these three brains, evolution on the hoof, dressed in tailcoats and long underwear. The plot — there actually is one — revolves around the house in which they grew up. Only youngest brother Sascha (Geoff Sobelle) has continued to live there, caring for their mother who has recently died.

Oldest brother Pyotr (Gabriel Quinn Bauriedel) and middle brother Nikolai (Dito van Reigersberg) have come back, ostensibly for Sascha’s birthday, but really to sell the house. Each brother’s personality correlates to the kind of brain he is identified with. When Pyotr is unable to to tell Sascha their decision, Nikolai just goes ahead and sells it to gardener Dmitri. James Sugg plays this bashful, stammering, panicky “good guy,” who is Chekhov’s alter ego; he also, necessarily, plays Chekhov.

Sugg’s restrained, seemingly unemotional Chekhov speaks almost without moving his lips, holding conversations with himself, merely turning his head and removing his hat to become the creator’s creature; by the end of the play Dmitri will have become Chekhov. Thus the play becomes a brilliant demonstration of theater-making, complete with a red velvet curtain. Chekhov announces “The five rules of theater: Every play has four acts; Keep the tragedy offstage; Who owns the house? Who owns the orchard? Keep it clean, keep it civil.”All the performances are marked by the verbal and physical agility that Pig Iron always delivers. Sugg is the thrilling, still center of the show — the circus ringmaster, capturing that essence of the tragicomic we call Chekhovian. Even the sound design, built on Russian folksongs and sobbing violins, is somehow both melancholy and hilarious.

Chekhov Lizardbrain

The Latvian Society, Philadelphia PA.; 114 seats; $30 top

Production

A Pig Iron Theater Company presentation of a play in one act by Robert Quillen Camp. Directed by Dan Rothenberg.